Before you get too far along with your construction, sit down and calculate the cost of a set of new sails (say four), a set of full instruments, and say just the interior cushions - add these numbers up and you have a reasonable budget for purchasing a nice 25'', built by professionals, in the water, ready to go.

You can go ahead with your dream, but do so understanding that you will pour a lot of $$$ into a hole not even in the water, unlikely to ever be finished, that will end up worth probably a third or a half of the cost of the parts you have yet to buy...

My advice, drive the trailer to the dump, buy a sailboat, and go sailing.